svcrdma: Add lockdep class keys for transport locks

Two svcrdma-related transport locks can become quite contended.
Collate their use and make them easy to find in /proc/lock_stat for
better observability.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

net/sunrpc/xprtrdma/svc_rdma_transport.c

@@ -125,6 +125,9 @@ static void qp_event_handler(struct ib_event *event, void *context)
 static struct svcxprt_rdma *svc_rdma_create_xprt(struct svc_serv *serv,
 						 struct net *net, int node)
 {
+	static struct lock_class_key svcrdma_rwctx_lock;
+	static struct lock_class_key svcrdma_sctx_lock;
+	static struct lock_class_key svcrdma_dto_lock;
 	struct svcxprt_rdma *cma_xprt;
 
 	cma_xprt = kzalloc_node(sizeof(*cma_xprt), GFP_KERNEL, node);
@@ -141,8 +144,11 @@ static struct svcxprt_rdma *svc_rdma_create_xprt(struct svc_serv *serv,
 
 	spin_lock_init(&cma_xprt->sc_lock);
 	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
+	lockdep_set_class(&cma_xprt->sc_rq_dto_lock, &svcrdma_dto_lock);
 	spin_lock_init(&cma_xprt->sc_send_lock);
+	lockdep_set_class(&cma_xprt->sc_send_lock, &svcrdma_sctx_lock);
 	spin_lock_init(&cma_xprt->sc_rw_ctxt_lock);
+	lockdep_set_class(&cma_xprt->sc_rw_ctxt_lock, &svcrdma_rwctx_lock);
 
 	/*
 	 * Note that this implies that the underlying transport support